The present invention relates to an apparatus for lashing utility cables to a support strand, and more specifically to a cable lasher that can be used in lashing a cable to a bare support strand or a support strand lashed to other cable.
Utility cables, such as telephone cables, are frequently routed by connecting the cables to overhead support wiring, or support strands, that are suspended from a series of utility poles. In an effort to prevent the telephone cable from sagging between adjacent poles, the cable is frequently tied or xe2x80x9clashedxe2x80x9d to a support strand that is tightly strung between the poles. For this purpose, a conventional lasher is pulled along the support strand to lash the cable to the strand. Before a lasher is used, the cable is loosely supported by temporary support brackets hung from the support strand. The lasher is then mounted on the support strand in position to engage the loosely supported cable. One or more coils of lashing wire are loaded onto the lasher, and a free end of lashing wire is clamped to the strand or otherwise secured at a starting point. The lasher is then pulled along the support strand. The loosely suspended cable slips through the front end of the lasher as the lasher moves along the strand. As the lasher is pulled along the strand, the lashing wire is helically wrapped around the cable and the strand to bind the cable to the strand. Reverse movement of the lasher is typically limited to minimize unwinding and loss of tension of the helically lashed wire.
The lasher rides along the top side of the strand and typically lashes the cable to the underside of the strand. When a strand is lashed to a cable for the first time, a locking bar on the lasher may be locked across the underside of the strand to hold the lasher securely on the top of the strand. When cable is being xe2x80x9coverlashedxe2x80x9d, that is, when cable is lashed to a strand that is already lashed to another utility line or cable, the lasher must ride over both the strand and the other utility line. In such an arrangement, the locking bar cannot be used. Typically, the locking bar is designed to lock around the relatively small diameter of the strand, and therefore does not have adequate clearance to lock around both a strand and a utility line already lashed to the strand. Therefore, it would be desirable for the locking bar to be repositioned and secured outside the path of the strand and the previously lashed cable when overlashing is performed. It would also be desirable to provide a suitable support structure on the frame to ensure that the cable is fed into the frame of the lasher as smoothly as possible.
In light of the foregoing, the present invention provides a cable lasher for securing telephone and transmission cables to a support strand strung in the air between utility poles. The cable lasher is operable to lash cable to a bare support strand, or to overlash cable onto a previously lashed support strand and cable.
In general, the cable lasher is movable along the support strand so that the transmission cable is fed through the lasher. The lasher includes a hollowed support frame having a central longitudinal channel or passageway for receiving the cable. The channel may extend the length of the lasher. A rotating drum is mounted relative to the frame and has an opening that aligns with the channel in the frame. As the lasher is moved forwardly along the support strand, a gearbox translates linear movement of the lasher along the support strand into rotational movement of the drum. For example, the support strand may contact and drive one or more drive wheels which in turn drive the gearbox. In operation, the gearbox causes the drum to rotate about the cable as the cable lasher rides on the support strand.
The rotating drum may contain at least one coil of lashing wire for lashing the cable to the support strand. Lashing wire is fed from the coil and through a series of pulleys or guides before being wrapped around the strand and cable. In use, the lasher is mounted on a support strand in position to receive a loosely supported cable. The free end of the lashing wire is then tied off on or near the strand prior to operation of the lasher. As the lasher begins to move along the strand, the drum starts to rotate about the cable and the strand creating tension in the wire. Then, wire is pulled from the coil and helically wraps around the cable and the support strand, lashing the two together.
In operation, the cable lasher is clamped over the support strand so that the cable is fed through the hollow channel in the lasher. The lasher is pulled from the ground by a worker using a handline, or by a line connected to a moving vehicle or capstan winch. As the lasher rides on the support strand, the drive wheel assembly causes the drum to rotate. In a specific arrangement, a drive wheel may be mounted on a common axle with a respective bevel gear of the gearbox to effect the translation of linear motion of the lasher into rotational motion of the bevel gear. Multiple drive wheels may be utilized. The bevel gear further translates torque to other gears of the gearbox to rotationally propel the drum. As the drum rotates, lashing wire from the coil is helically wrapped around the cable and the support strand, thereby lashing the cable and strand together.
The drive wheel assembly and gear box operate during normal use to limit the rotational motion of the drum in a single rotational direction only. As the lasher rides along the strand, a latch mechanism prevents reverse rotation of the drum. For this purpose, the latch mechanism may include a one-way latch which functions to engage a brake gear integrally mounted with the bevel gear to restrict the bevel gear from rotating in a reverse direction. For example, the latch may include a latch pawl for engaging sprocket grooves on the brake gear to prevent reverse rotation of the bevel gear and, as a result, the drum. As such, the one-way latch restricts the drum from rotating in the reverse direction. The one-way latch also restricts the drive wheel from rotating in a reverse direction, limiting reverse movement of the lasher on the support strand. This arrangement maintains tension in the lashing wire to provide a consistently tight wind and prevent unwinding of the lashing wire. A user-operated release may be actuated at any time to disengage the one-way latch from the brake gear to permit reverse movement of the lasher on the strand and reverse the rotation of the drum. If reverse rotation of the drum is needed, or if reverse motion of the lasher on the strand is required, the user-operated release can be used to disengage the one-way latch from the brake gear of the gearbox. When the one-way latch is disengaged from the brake gear, the drum is free to rotate in either direction, and the lasher is free to move along the strand in either direction.
The one-way latch may include an adjustment mechanism to control the amount of engagement between the latch and the brake gear. For this purpose, the latch arm or pawl may be connected to a linkage that shifts or reciprocates laterally as the latch pawl is moved into and out of the brake gear sprocket grooves or teeth. The range of lateral motion of the linkage controls the depth at which the latch fits between the sprocket teeth. This range of motion in the linkage may be adjusted by use of an eccentric screw disposed through a bore in the linkage. As the concentric screw is turned, a lateral shift will be effected between the linkage and the pawl.
A front gate assembly may be mounted on the front end of the cable lasher for lifting the loosely hung cable into position for lashing with the strand. The front gate assembly may be swung open and closed to allow the lasher to be placed over a section of the strand and cable so that the strand and cable are received into the channel. The front gate assembly includes a roller that lifts the cable as the cable is fed into the lasher. The roller provides a smooth surface for supporting the cable so that the cable may be fed into the lasher without encountering sharp edges that could pinch the cable or generate a large amount of friction. The cable may shift laterally as it enters the channel of the lasher. Therefore, the roller may span generally the entire width of the channel. In a specific arrangement, the roller may have a width generally equal to the entire width of the channel to maximize rolling contact with the cable over the largest range of lateral displacement as the cable enters the channel. The front gate assembly may also include a front support bar that supports sagging cable being fed into the lasher. The front support bar has a rounded mouth edge upon which sagging cable may rest so that a sagging cable being fed into the lasher may be supported without encountering sharp edges.
A tapered front cover or cowl may be provided on the front end of the lasher to function as a nose cone to prevent objects from catching on the cable lasher as it rides along the support strand. The tapered front cowl covers the front end of the lasher and has a narrow front portion and a wider tail portion having an outer diameter that is slightly larger than the outer diameter of the rotatable drum. The tapered shape of the front cowl prevents objects from catching on the rotating drum as the cable lasher rides along the support strand.
A support strand lock may also be provided toward the front end of the lasher to secure the lasher about the support strand while still allowing the lasher to slide along the strand. For this purpose, the strand lock may include a generally horizontal locking bar that can be rotated about a pivot between an open position oriented generally longitudinal to the channel and the support strand to permit the device to be mounted upon the strand and a closed position generally transverse to the channel and the strand to permit the lasher to be secured onto the strand. The locking bar may also be movable between a raised engaged position and a lowered disengaged position by a lever handle. The bar can also be raised, or pulled inwardly into the frame, into contact with the underside of the support strand to maintain the strand in contact with the drive wheel of the lasher. Alternatively, the bar may be moved into a lowered position, outwardly from the frame and out of contact with the strand. In the lowered position, the locking bar may be pivoted between its closed orientation, in which the locking bar is generally perpendicular to the support strand and channel, and its open orientation, in which the locking bar is rotated out of the channel to an orientation generally parallel to the support strand. In the closed orientation, the locking bar can be raised by the lever handle to engage the strand. A first bracket mounted at the side of the channel opposite the pivot for the bar receives and captures the free end of the locking bar when the bar is raised so that the locking bar is restricted from pivoting out of engagement with the strand. In the open orientation, the locking bar can be raised by the lever handle to move the free end of the bar into a second bracket mounted on the same side of the channel as the pivot. Once in the second bracket, the locking bar is secured away from the channel so that the frame can be mounted over a strand and cable without interference from the locking bar.